Gas fired water heater



July 28, 1931. H. J. CARSON GAS FIRED WATER HEATER Filed May 11, 1929 lllllillllllllillll |\I\Ull\ll Patented July 28, 1931 HIRAM J. CARSON; OF CEDAR RAPIDS, IOWA GAS FIRED WATER HEATER hpplieation filed Kay 11, 1929. Serial No. 362,308.

The features of this simple, inexpensive and highly efficient heater are shown in the m drawings, in which Figure 1 is a sectional view of the water heater structure.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Fi ure 3 is a sectional view on the line 33 of Figure 1.

Figure 4 is an enlarged view of a section indicated by dotted outline in Figure 1.

In Figures 1 and 2 a water contaming tank 20 5 with a vertical tube 7 extending through it is shown placed" concentricallywithin an insulatingcasing fi with an annular space and an upper space 13 between them, and both supportedin any suitable manner as by a as base 24. Y

The bottom of the annular space 15 o ens into a vent 16 shown equipped with a raft hood 16m A burner 9, preferably having raised flame ports to permit complete aeration of the gas and flame and burning the gas in a relatively high flame and large volume for a given burner area, for operation by hand or any suitable automatic means, and-supported in any suitable manner as by a bracket 22, is

shown with the flame 8 extending well with{ in the tube 7.

At 9a is indicated a heat radiating element for increasing the amount of heat transferred by radiation to the tube 7, said element 9a being of any suitable heat radiating material and relatively vertically elongated so as to extend up into thelower portion of the tube 7. i

This radiating element is preferably inthe form. of a truncated cone substantiall I shown in Figure 1 with the small end own and positioned within the circle of flame ports, said lower end of said element having a smaller diameter than the flame port circle so as to permit the aeration and partial burning of the gas before it strikes the radiating material. The flame is thus brought into intimate contact with and licks the heat radiat-' ing material and any small projections there-.' on as indicated in 9a and raises'it to a relatively high temperature.

Combustion of the gas is thereby accelerated and completed and a sufiiciently large proportion of the total heat is liberatedin radiant form to insure the relatively even heating of the water throughout the tank.

Burners adapted for the use of high pressure gas with a suitable air inspirator or for an air blast may be used when desired for further increasing the rate of gas burning in a given heater. Such burners are preferably of the radiant type so a substantial amount of the heat in the gas burned may be liberated as radiant heat and be immediately absorbed by the water through the tube wall at the lower portion thereof.

- Secondary air to the burner may be limited by any suitable means as an opening 11 in the bottom plate 10 or placing the burner of a sufliciently large area close to or into the tube for restricting the opening as desired.

Water outlet and inlet pipes are indicated by 20 and 21 respectively.

. A core buster 17 of any suitable design is shown disposed in the tube 7 supported as by a pin 19 and centered by pins 18.

A condensation drain may be used as indicated at 23.

In Figure 3 a tank 5 is shown placed eccentrically within the insulating casing 6. The

annular space 15 is narrowed near the flue outlet 16 and gradually enlarges to a maximum width opposite the flue outlet. This arrangement further assures the uniform descent of the gases around the tank and the utilization of the heating surface provided in the watertank wall by equalizing any tendency for the gases to short circuit from the top opening 0 tube 7 at 12 to the flue opening 16.

In Figure 4 the curved arrows (1 indicate the movement of the as particles toward the water tank 5 in their ownward travel in the annular space 15. The arrows b indicate the relative velocity and temperature of the gas particles in the annular space: the longer the arrows the greater the velocity and the lower the temperature of the gas particles.

The particles closest to the water tank have the lowest temperature and the greatest downward velocity. y

In the operation of the heater, the heat radiated by the flame 8 and radiant burner 9 and 9a is immediately absorbed by the water through the tube 7 The burned gases in passing upwardly through the tube are continually cooling and the coolest portion ofthe gas column is that close or next to the tube wall. As this cooling progresses, and the density of the gas particles increases these cooler particles move more and more slowly and tend to have a downward direction in relation to the more rapidly risingand hotter.

gases in the center of the gas column.

A relatively cool thick insulating layer of gas is thereby interposed between the hot gases and thetube column.

The thickness of this cool gas layer is reduced by increasing the velocity of the gases through the tube by means of a core buster 17 which diminishes the gas passage area. The burned gases accordingly have a greater upward velocity around the core buster, the thickness of the insulating film near the tube is reduced and the rate of heat transfer is'in creased- The burned gases pass out of the tube at the top 12 and over the tank through space 13 and downwardly around the outside of the tank through annular space 15 and thence out through vent 16'.

The gases descend in a relatively uniform manner around the tank in the annular space 15 with the cooler gas particles near the tank Wall continually descending at a relatively high velocity whereby the hotter gas particlesare continually drawn toward the tank surface with a relatively high rate of heat transfer and a nearly complete absorption of the heat in the gases by the tank wall and water before the gases are discharged through the outlet 16.

By referring to the Figures 1 and 2, it will beobserved that the heating surface provided by the tank-wall in the down draft assage between the tank 5 and insulation 6 15 substantially greater than that in the up draft assage in the tube 7. v

Wit gases descending around the tank wall, provision is made for a relatively high rate of heattransfer to the water through the relatively large tank wall area in this down draft passage.

The heatingsurface in the-down draft point of any water vapor in them. The forpassage is accordingly ada ted for the absorption of so much heat rom the burned gases that these gases may leave the up draft passageway substantially above the dew outer'passage.

mation or depositing of condensates in the up draft passage is thereb avoided.

By again re erring to will. be observed that the cross sectional area of the tube 7 for the up draft is substantially less than the cross sectional area of the down draft passage provided between the tank 5 and the insulation 6.

By'reason of the difference in the areas of these passages for the products of combus tion and the higher temperature of the up draft gases the upward movement of the products of combustion within the tube 7 is faster than the rate of down travel in the Because of this higher velocity the insulating effect of the gasfilm between the rising column of hot gases and the tube wall as reviouslydescrihed is reduced and may be urther reduced by the use of a core buster as above described.

As the gases are cooling as they are rising in this up draft passageway a proportionately greater amount of heat is transferred in the lower portion of this tube than in the top which reduces the rate of transfer, as the gases rise in the tube and the water in the lower .portion of the tank receives more heat than that in the upper portion.

In the down draft passageway with its greater amount of heating surface and as the gases descend as they are cooling and provide for a relatively high rate of heat transfer in this passage, the gases are hottest at the top and as a result less and less heat is available and transmitted to the water as these gases descend around the tank.

The heat radiating element in the lower portion of the tube increases the heat trans fer to the water in the lower portion of the tank and with the heat transferred to the water in the up draft passage from the sensible heat of the burned gases offsets the high rate of heating the water in the top portion of the tank by the gases in the down draft passageway and relatively even heating of the water throughout the tank is thereby effected.

With heat radiating material used in any desired amount the proportion of the total.

heat of the gas burned liberated as radiant heat and absorbed through the tube in the lower portion of the tank may be varied within relatively wide limits and the water temperatures in the top and bottom of the tank' may be thereby kept within the limits desired.

The invention accordingl provides simple and highly eflicient means {hr recovering the radiant heat from the flame; increasing the amount of heat liberated as radiant heat in the burner. and core buster zones and the immediate recovery thereof in the water; increasing the velocity of the burned gases in the tube and the'rate of heat transfer thereigures 1 and 2 it' I ture to the flue outlet. As .the function of v the burner element 9a is to receive heat on its exterior from the flame and to transmit the same by direct radiation, it will be evident that a heat radiating element of this character is applicable to any type of water heater in which a tubular structure of any type is employed to transmit heat to a surrounding body of water or other liquid.

The apparatus as described is simple, inexpenslve, easy to manufacture, and provides highly eflicient means for heating water with as. g Having described my invention, I claim: 1. A gas fired water heater comprising: a water storage tank having a vertically arranged tube therein extending therethrough and providing an uptake passage; a heat insulating casing enclosing said tank and spaced therefrom along the sides and at the top and thereby providing a downtake passage in communication with the uptake passage; said downtake passage having an outlet in the lower portion thereof; a gas burner at the bottom of said tube; and a heat radiating element disposed within the lower portion of said tube, the heat received by said element from the burner being radiated directly to the lower portions of the tube and the products of combustion passing upwardly through the tube and thence downwardly around the tank to said outlet, the uptake passage provided by said tube and the downtake passage being so related as to produce a more rapid upward flow of the products of combustion therethrough than in the downtake passage around the tank.

2. A gas fired water heater comprising: a water storage tank having a vertically arranged tube therein extending therethrough and providing an uptake passage; a heat insulating casing enclosing said tank and spaced therefrom along the sides and at the top and thereby providing a downtake passage in communication with the uptake passage, said downtake passage having an outlet in the lower ortion thereof; a gas burner at the bottom of said tube and a heat radiating element disposed within the lower portion of said tube, the heat received by said element from the burner being radiated directly to. the lower portions of the tube and the products of combustion passing upwardly through the tube and thence downwardlyaround the tank to said outlet, the heating surface areas ,in the uptake passage rovided by said tube being less than in the owntake passage and said heat radiating element being so related to said areas that the Water is heated to a relatively uniform temperature throughout the tank.

having communicating passages for the upward and downward flow of the productsof combustion, the area of the heat transfer surface for direct heating by the products of combustion in said uptake passage being materially less than the area of the heat transfer surface for direct heating by the products of combustion in said downtake passage, said downtake passage having an outlet in the throu h the downtake passage to said out-let,-

where' y the water is heated to a relatively uniform temperature throughout the tank and the products of combustion are caused to enter said.downtake passage at a temperature above the condensation point of the Water vapor therein.

In testlmony whereof I affix my signature.

HIRAM J. CARSON. 

